Lead Java Developer

Job Title: Sr Java Card / eSIM Applet Developer Location: India Pune Reports To: Engineering Team Lead About Telna Telna provides Mobile Network Operators (MNOs), Communication Service Providers (CSPs), and Original Equipment Manufacturers (OEMs) with a fully managed global cellular connectivity platform. With access to the largest 2G–5G and LTE-M coverage from over 800 radio network operators—300 of which are direct partners—across 200 countries, Telna empowers seamless, high-performance connectivity worldwide. Our global multi-network connectivity platform simplifies integration, offering localized break-out capabilities via cloud infrastructure. With a single integration into Telna’s platform, millions of devices are powered by resilient, multi-network connectivity—enabling a wide array of innovative cloud-based solutions. Position Overview The Senior eSIM Applet Developer will own the entire lifecycle of eSIM Java applet development — from requirements definition and architecture through coding, testing, certification, and deployment. This role requires deep technical expertise in Java Card, SIM/eSIM environments, and secure element application development. You will collaborate with product, platform, and QA teams to design, develop, and maintain Telna’s next-generation eSIM applets, ensuring compliance with GSMA, ETSI, and GlobalPlatform standards. Key Responsibilities - Own full applet lifecycle: from requirements gathering, design, and development to testing, certification, and release. - Develop and maintain Java Card applets for SIM, USIM, and eSIM (eUICC) environments. - Implement, debug, and troubleshoot applet logic on various SIM/eSIM platforms and toolchains. - Collaborate with OEMs, chipset vendors, and MNOs to integrate and validate applet functionality. - Ensure compliance with GSMA, ETSI, and GlobalPlatform standards for SIM/eSIM applets. - Conduct code reviews, test case design, and performance analysis. - Work closely with QA to automate testing and validation in both simulated and real device environments. - Prepare and maintain technical documentation (design specs, test plans, release notes). - Stay current with advancements in eSIM technology, secure element design, and Java Card platform updates. Required Qualifications - Bachelor’s or Master’s degree in Computer Science, Electrical Engineering, or related field. - 5+ years of hands-on experience developing Java Card applets for SIM, USIM, or eSIM. - Deep understanding of: - Java Card 3.X / GlobalPlatform 2.X standards - APDU communication and ISO 7816 - Security domains, SCP02/SCP03, and OTA mechanisms - Experience with SIM/eSIM development and debugging tools (Gemalto, G&D, Thales, VALID, etc.). - Strong knowledge of GSMA SGP.02 / SGP.22 / SGP.32 specifications. - Experience deploying and testing applets on UICC/eUICC hardware. - Proficiency in troubleshooting using logs, traces, and APDU-level analysis. - Solid understanding of cryptography and key management in secure element contexts. - Excellent problem-solving skills and attention to detail. - Strong communication and documentation skills. Preferred Qualifications - Experience with remote SIM provisioning (RSP) environments. - Knowledge of OTA platforms and backend integration with SIM lifecycle management systems. - Familiarity with embedded systems or secure hardware modules. - Previous work in telecom or IoT connectivity environments. Why Join Us - Contribute to the advancement of cutting-edge telecom technologies and infrastructure - Collaborate with a diverse, experienced, and multicultural team of engineers and industry professionals - Enjoy a flexible work environment with remote work options - Receive a competitive salary and comprehensive benefits package - Grow your career through professional development opportunities and technical training